We know that as a mother you have a million things on the go and you don't have time to order a pump, only to find that you need an insert or different flange size after the fact. Take the guess work out of the equation before ordering with this handy, download-able flange/insert sizing chart.
Simply print this out in the comfort of your own home, follow the instructions and you're good to go.
Now go back to being the amazing mama that you are!